There is no consensus on global warming..

Jeff Jacoby of the Boston Globe does a fine job of looking at the evidence...

In 2003, environmental scientists Dennis Bray and Hans von Storch surveyed 530 of their peers in 27 countries on topics related to global warming. One question asked: "To what extent do you agree or disagree that climate change is mostly the result of anthropogenic causes?" On a scale of 1 (strongly agree) to 7 (strongly disagree), the average score was 3.62, reflecting no clear consensus.

Asked whether abrupt climate changes will wreak devastation in some areas of the world, the percentage of scientists strongly agreeing (9.1) was nearly identical to the percentage strongly disagreeing (9.0). Another question asked: To what degree might global warming prove beneficial for some societies? A striking 34 percent of the scientists answered 1 or 2 (a great degree of benefit); just 8.3 percent answered 6 or 7 (very little/no benefit).

Plainly, the science isn't settled. It changes all the time.

Take the latest report of the Intergovernmental Panel on Climate Change. Unlike its previous report in 2001, which foresaw a possible rise in sea levels over the next century of around 3 feet, the new report cuts that figure in half, to about 17 inches.

Why the revision? "Mainly because of improved information," the IPCC notes in the fine print. It goes on to note that even its latest estimate involves some guesswork: "Understanding of these effects is too limited to assess their likelihood." The science is getting better, but it's far from settled.

Climate scientists are still trying to get the basics right. The latest issue of Science magazine notes that many researchers are only beginning to factor the planet's natural climate variations into their calculations. "Until now," reports Science, "climate forecasters who worry about what greenhouse gases could be doing to climate have ignored what's happening naturally. . . . In this issue, researchers take their first stab at forecasting climate a decade ahead with current conditions in mind."

Their first stab, please note, not their last. The science of climate change is still young and unsettled. Years of trial and error are still to come. Al Gore notwithstanding, the debate is hardly over.